We are continuing our efforts to determine the biochemical basis for the development of emphysema. We are using the alpha-1-P.I. deficiency system as a model and we have now isolated both the inhibitor and the enzyme (elastase) believed to be responsible. The mechanism by which these proteins interact is currently being examined. Bibliographic references: P. Mallory and J. Travis. "Human Pancreatic Enzymes: Purification and Characterization of a Nonelastolytic Enzyme, Protease E, Resembling Elastase." Biochemistry 14, 722 (1975). R. Pannell, D. Johnson, and J. Travis. "Isolation and Properties of Human alpha-l-Proteinase Inhabitor." Biochemistry 13, 5439 (1974.)